Single reel cartridges for magnetic tape are well known. For instance, one type of single reel cartridge used with magnetic tape is disclosed in U.S. Pat. Nos. 4,775,115; 4,452,406; 4,426,047; and 4,383,660. Such single reel cartridges provide a number of advantages over more conventional, large tape spool reels. Data is more compactly stored on single reel cartridges than on spool reels, providing for faster data retrieval times and reduced physical storage space requirements. In addition, single reel cartridges are easily manipulated by automated handling equipment, facilitating the automated retrieval of the cartridges from storage racks, and the automated insertion and removal of retrieved cartridges from cartridge data reading devices.
Unfortunately, the very characteristics of single reel magnetic tape cartridges that provide for the above noted benefits present physical security issues that have heretofore not been successfully addressed. In particular, single reel tape cartridges are by design compact, and can easily be placed into a brief case, purse, or pocket, and transported undetected out of designated storage areas. The security problem is exacerbated by the large amount of data that can be stored on an individual single reel cartridge.
Data banks made up of single reel magnetic tape cartridges can typically include sensitive financial information, confidential personnel data, proprietary engineering data and similar types of controlled information. On line access to such information is controlled through the use of computer pass words and other information handling techniques. Maintaining physical security of information media such as single reel magnetic tape cartridges, however, is equally important, and can be accomplished only through storing the cartridges in a controlled access work space and providing continuous monitoring of the cartridges.
Electronic article surveillance systems for monitoring the egress of sensitive objects from controlled spaces are well known. For instance, markers formed from a piece of high permeability magnetic material can be placed within the binding of a library book. Spaced apart detection panels are then placed across the access points to and from the library. The panels include field coils and detector coils for producing a magnetic field across the access point for detecting the passage of a marker between the panels. If a person attempts to carry a book through the magnetic field presented by the panels, without first desensitizing the marker within the book binding or the magnetic field, the presence of the marker will be detected and an alarm initiated.
Heretofore, electronic material surveillance systems have only enjoyed limited acceptance in monitoring single reel tape cartridges within controlled work spaces. While markers used in such systems can be applied to the external surfaces of conventional single reel magnetic tape cartridges, markers carried by conventional cartridges can be easily removed or otherwise tampered with. Moreover, markers carried on the external surfaces of a conventional cartridge can interfere with the handling of the cartridge by automated cartridge handling equipment.
Most often, single reel magnetic tape cartridges have sealed, internal tape carrying compartments that cannot be ordinarily accessed without disassembling or destroying the cartridge. Accordingly, a single reel magnetic tape cartridge especially designed for the placement of electronic article surveillance markers within the cartridge would provide for the successful employment of an electronic article surveillance system in monitoring the physical security of the cartridges.